We have developed a high-sensitivity, low-noise femtosecond imaging technique based on pump-probe time-resolved measurements with a standard CCD camera. The approach used in the experiment is based on lock-in acquisitions of images generated by a femtosecond laser probe synchronized to modulation of a femtosecond laser pump at the same rate. This technique allows time-resolved imaging of laser-excited phenomena with femtosecond time resolution. We illustrate the technique by time-resolved imaging of the nonlinear reshaping of a laser-excited picosecond acoustic pulse after propagation through a thin gold layer. Image analysis reveals the direct 2D visualization of the nonlinear acoustic propagation of the picosecond acoustic pulse. Many ultrafast pump-probe investigations can profit from this technique because of the wealth of information it provides over a typical single diode and lock-in amplifier setup, for example it can be used to image ultrasonic echoes in biological samples.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1364/OE.22.004590 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
3D Finite Element Modeling of Femtosecond Laser Trabeculotomy.
Lasers Surg Med
January 2025
ViaLase Inc., Aliso Viejo, California, USA.
Objectives: Femtosecond laser image guided high precision trabeculotomy (FLigHT) is a novel open-angle glaucoma treatment. The procedure non-invasively creates aqueous humor (AH) drainage channel from the anterior chamber (AC) to Schlemm's canal (SC) through the trabecular meshwork (TM) to decrease intraocular pressure (IOP). The purpose of this study was to develop a 3D finite element model (FEM) of the FLigHT procedure and to simulate clinical results for different drainage channel cross-sectional areas.
View Article and Find Full Text PDFFrom femtoseconds to minutes: Spectroscopic study of optically induced thermal diffusion in aqueous solution of rhodamine B.
Photochem Photobiol
December 2024
Institute of Chemistry, State University of Campinas, Campinas, São Paulo, Brazil.
Given that non-equilibrium molecular motion in thermal gradients is influenced by both solute and solvent, the application of spectroscopic methods that probe each component in a binary mixture can provide insights into the molecular mechanisms of thermal diffusion for a large class of systems. In the present work, we use an all-optical setup whereby near-infrared excitation of the solvent leads to a steady-state thermal gradient in solution, followed by characterization of the non-equilibrium system with electronic spectroscopy, imaging, and intensity. Using rhodamine B in water as a case study, we perform measurements as a function of solute concentration, temperature, wavelength, time, near-infrared laser power, visible excitation wavelength, and isotope effect.
View Article and Find Full Text PDFAn NIR-II Two-Photon Excitable AIE Photosensitizer for Precise and Efficient Treatment of Orthotopic Small-Size Glioblastoma.
Adv Mater
December 2024
School of Science and Engineering, Shenzhen Institute of Aggregate Science and Technology, The Chinese University of Hong Kong (CUHK-Shenzhen), Shenzhen, Guangdong, 518172, P. R. China.
The existence of residual small-size tumors after surgery is a major factor contributing to the high recurrence rate of glioblastoma (GBM). Conventional adjuvant therapeutics involving both chemotherapy and radiotherapy usually exhibit unsatisfactory efficacy and severe side effects. Recently, two-photon photodynamic therapy (TP-PDT), especially excited by the second near-infrared (NIR-II) light, offers an unprecedented opportunity to address this challenge, attributed to its combinational merits of PDT and TP excitation.
View Article and Find Full Text PDFDual Infrared 2-Photon Microscopy Achieves Minimal Background Deep Tissue Imaging in Brain and Plant Tissues.
Adv Funct Mater
October 2024
Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA.
Traditional deep fluorescence imaging has primarily focused on red-shifting imaging wavelengths into the near-infrared (NIR) windows or implementation of multi-photon excitation approaches. Here, we combine the advantages of NIR and multiphoton imaging by developing a dual-infrared two-photon microscope to enable high-resolution deep imaging in biological tissues. We first computationally identify that photon absorption, as opposed to scattering, is the primary contributor to signal attenuation.
View Article and Find Full Text PDFAn analysis of the structural changes of the oxygen evolving complex of Photosystem II in the S and S states revealed by serial femtosecond crystallography.
Biochim Biophys Acta Bioenerg
December 2024
Laboratory of Computational Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA. Electronic address:
Photosystem II (PSII) is a unique natural catalyst that converts solar energy into chemical energy using earth abundant elements in water at physiological pH. Understanding the reaction mechanism will aid the design of biomimetic artificial catalysts for efficient solar energy conversion. The MnOCa cluster cycles through five increasingly oxidized intermediates before oxidizing two water molecules into O and releasing protons to the lumen and electrons to drive PSII reactions.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!